A liquid-level sensor is known from DE 197 57 924 A1. Two tubular electrodes disposed inside one another are used to determine the dielectric constant or the specific resistance value of oil. The electrodes are contacted by spring elements.
An additional sensor array for determining the resistance value of oil is described in DE 195 11 556 C1. Two cylindrical electrodes are disposed coaxially and insulated from one another by spacer elements, The liquid-level sensor has a mounting flange on a housing edge.
The housing of the liquid-level sensors is made of plastic. To this end the capacitive measuring elements are extrusion-coated using an appropriate plastic. The affixation in a cavity or in a duct to a cavity may be implemented with the aid of a flange. Sealing is typically accomplished by an adhesive agent.